It used to be that if you muttered something about bombs and the president on the telephone, you could get two men in black suits at your door. Social media is monitored more than that, though I don't think you get the same response unless you're going through customs. Or are middle eastern.
That's what people remember about 1984, but that actually only applied if you were middle class like Winston, since they didn't control his boss nor any of the proles.
So the actual message of the book was that living in England sucks, which as far as I can tell is still true.
The state has mostly learned that allowing a measure of dissent and criticism is fine, and even strengthens its claims to legitimacy, as long as it's of a mostly non-revolutionary character. This is why Noam Chomsky is allowed to inveigh impotently against American imperialism while keeping his university sinecure and book deals.
On the other hand, if you start something like the Black Panthers, or MLK's planned march on DC, or the Ferguson protests, then something much more final than prison may be used to get rid of you.
Much more sophisticated than jail.